Key elements in accurate shooting, especially handgun shooting, are steady aim and steady trigger pull. If a person has difficulty pulling a trigger due to inadequate finger pull strength, either the trigger cannot be pulled completely at all, or the hand and arm may shake due to the required effort. Thus, either the weapon cannot be fired or the aim cannot be well maintained. Furthermore, the pull of the trigger may be jerky and the timing of the shot may be unpredictable.
Handgun grips are shaped so as to utilize the forefinger to pull the trigger. This finger is nearest to the trigger and frees the (ordinarily) stronger middle finger for a good grip on the gun. If a shooter has difficulty pulling the trigger with his or her forefinger, he or she may try to use the middle finger instead. This is not recommended in a one-handed shot because the grip is left to the two remaining, usually weaker, fingers.
Inadequate forefinger strength combined with sudden or initial use of a firearm can also lead to injury, which further delays firearm training. Sometimes people learn they have inadequate forefinger strength when they first attempt to fire a handgun, or first fire a handgun notable for hard trigger pull such as a large caliber uncocked revolver. This can result in a type of injury known as “trigger finger,” wherein the tendons of the forefinger on top of the hand are strained.
To solve the problem of inadequate forefinger strength, affected handgun users may exercise the grip using common grip-strengthening devices such as spring-loaded hand grips. This strengthens the entire grip and all fingers acting in concert but does not strengthen the forefinger per se, especially in the grip configuration in which the flexor muscle of the forefinger is extended while the others are contracted.